The eight candidates cleared by the 12-member Guardian Council wrapped up their debate season last week. Two of the candidates have since dropped out of the race.
Supreme Leader Ali Khamenei said the debates were emblematic of the vibrant political culture in Iran.
"The remarks made by the eight candidates with eight tendencies and views in their televised and radio debates informed people of their different thoughts and views and showed the freedom of speech in the Islamic Iran," he was quoted by the semiofficial Fars News Agency as saying.
Debate topics ranged from cultural issues to the economy. Friday's debate, the last of three, focused on foreign policy.
Most of the remaining candidates are considered close allies of the ruling cleric. Former nuclear negotiator Hassan Rohani is the only reformist candidate left in the race.
Khamenei has ultimate say over Iranian affairs. The Guardian Council, which has the right to continue vetting the candidates, denied allegations it was putting pressure on Rohani.
Iranian presidential elections are scheduled Friday. Incumbent President Mahmoud Ahmadinejad is ineligible to compete because of term limits.
The remaining candidates are former Tehran Mayor Mohammad Qalibaf, former Foreign Minister Ali Akbar Velayati, chief nuclear negotiator Saeed Jalili, Rohani, former Oil Minister Mohammad Qarazai, and former military commander Mohsen Rezaei.